function road(){
	this.draw = function(){	
	ctx.drawImage(road_img_array[0],0,i+z,800,h,0,330+i+z,800,h);
	}
}

function drawRoad(img,src_y,src_h)
{
	ctx.drawImage(road_img_array[img],0,src_y,800,src_h,0,src_y+350,800,src_h);
}